PDA

View Full Version : A quick question about scary sharp



Joe Suelter
02-17-2003, 1:12 AM
What grits of sandpaper do you use for your scary-sharp? I thought about 220-400-600. Any reason to go beyond 600 grit? That puts a mirror like edge on chisels. I made a jig the other night with some scrap sheets, just to play around. Boy, you can really put an edge on chisels with this method!! I took my nastyest looking chisel (actually an old one that we found in a block basement wall we replaced-so it must be from 1937) and got it very sharp. Just thought I'd ask what you Pro's use.

J.R. Rutter
02-17-2003, 2:06 AM
Depends how you use them. I have a few nicer chisels that I go up to 1000 grit on - makes it easy to pare away fine shavings. But maybe wasted on roughing out or mortise chopping... Spring for a sheet of really fine paper and play around, and don't forget the back of the blade.

-JR

Jim Fuller
02-17-2003, 10:48 AM
If you will get an eye loupe you can see the difference in the edges. Then you can decide how sharp you want it. On my chisels and hand plane blades (I use a vertias guide) my final sharpening is with 2000 grit paper. I have this mounted on a peice of 1/4 inch glass. I probably couldn't tell the difference in using the tools if I didn't go this last step, but it makes me feel good. I like to get visitors, especially children, in my shop, show them one of my dad's old hand planes that I still use, write their name on a peice of wood and shave it off and give it to them. Impresses most kids, and some adults.

Joe Suelter
02-17-2003, 10:55 AM
Wow, Jim...that sounds impressive. I'll have to give that a try! I thought I was doing good with the 600. Thanks so much for your input.

Jim Fuller
02-17-2003, 11:34 AM
Actually, I will grind a profile on a new tool, if it isn't one I have already sharpened, then go to 240 or 400 grit depends on how much I need to remove to get angle right, then 800 and finally 2000. Then with the jig I have I can put a 2 degree secondary angle on it, I go back to 400 for a few strokes then 800 and 2000. Try it, you will impress yourself

Doug Hepler
01-14-2016, 11:36 PM
Joe,

Good choices. IMO sandpaper is the easiest, most effective way to go. Choice of grit depends on the condition of the tool. Normally, I touch up a sharp chisel or plane iron with 15 micron paper (about 600 CAMI). I have a strip of 5 micron paper (about 1200 CAMI) beside it and often will make a few passes on that as well. I use coarser grits like 220, 320 and 400 for minor reshaping and then finish as above. Most practical users of SS will say that you don't get much advantage from grits finer than 600 but I prefer that polished edge. I don't do much carving, but for cutting inlay with a knife I feel even finer grits are justified. I'll polish an edge with white rouge (about 5 microns) on a felt wheel.
BTW I prefer to touch up often, so I have learned how to hone by hand. Unfortunately I eventually wind up with a convex bevel. Then I pull out my honing jig (Veritas MKII) and 220 paper or even go back to a grinding wheel. It's much easier to sharpen by hand with a hollow ground or even a flat bevel.

Max Neu
01-15-2016, 6:20 AM
Typically you won't see much difference going finer initially. But the finer more polished the edge is,the longer it will stay sharp.

Andrew Pitonyak
01-15-2016, 10:30 AM
First, lets put this into context. A very rough correlation between CAMI and other sharpening media.



100 is about the same as a Shapton Pro 120
180 to 200 is similar to a Shapton 220
400 is between a 600 and 800 water stone.
600 is similar to a 1000 water stone.
1500 is similar to a Shapton Pro 5000 or a Norton 4000
2000 is about 1 micron, which is smaller than a Shapton 12000 (1.2 Micron)
2500, well, I do not know the average size, but, I show it as finer than Shapton 16000 (0.92 micron)


I do not know how accurate my numbers are, but, many people stop at their 1000 water stone, but, most go finer. More typical top ends are 5000 to 10000.

Green Compund I show at 0.5 micron on my cheat sheet, and many people here talk about using honing compound.

So, is 600 grit sandpaper sufficient? Yes, I think that it is for all but the most demanding tasks, but, the majority of water stone users go finer.

glenn bradley
01-15-2016, 11:12 AM
Sharpening is one of those subject that is sure to get a lot of replies. My scary sharp abrasive films go to .3 micron. I use marble "tile" for grits up to about 220 then switch to glass for 400, 15, 5 and then .3 micron. I also use a Worksharp, a Veritas jig, a Krell jig, diamond stones, etc. It depends what I am sharpening and what I use it for. YMMV.

Susumu Mori
01-15-2016, 11:14 AM
Can anybody suggest me which sand paper I should get?
I assume that you are using those with sticky back.
I once purchased Porter&Cable rolls with adhesive back, which ruined the surface of my granite with residual of glues and disintegrated sand papers stuck to the glue....

Mike Ontko
01-15-2016, 11:21 AM
I use a wet/dry paper with a light tack spray adhesive on a 3/8" thick piece of glass shelving (less than $20, I think at HD) in grits on one side ranging from 80 to 220 for rough shaping, and on the other side from 400 to 1000 for honing. The 1000 grit gets my plane blades and bench chisels to a nice mirror-like polish. I made up a leather strop board, thinking that using a polishing compound (white stuff, labeled as ultra fine) would give me an even better edge. But the compound I'd purchased must've been coarser than the 1000 grit paper because it only served to take away the mirror finish. I recently purchased a 4000 Norton stone, but haven't put it to use yet.

But getting back to your question, the 1000 grit seems to be "okay" for most general detail work (like M&Ts in ash and half lap dovetails in maple, but especially for light paring). I just wasn't satisfied enough with that, which is why I got the Norton stone for a final honing step.

Brian Henderson
01-15-2016, 12:53 PM
Can anybody suggest me which sand paper I should get?
I assume that you are using those with sticky back.
I once purchased Porter&Cable rolls with adhesive back, which ruined the surface of my granite with residual of glues and disintegrated sand papers stuck to the glue....

It doesn't have to be sticky backed, you can just use spray adhesive and it works fine.

Doug Hepler
01-15-2016, 1:11 PM
Susumu

My sandpaper sources are LeeValley/Veritas and Tools for Working Wood. Regarding the residue, acetone should wash off the gunk. I prefer PSA paper because the adhesive film is more even than I can apply myself. Think about it -- if you are trying to put an edge that is flat to 15 microns (or whatever) the surface of the sandpaper has to be at least that flat. If it's not the edge will catch the lumps and tear the paper. Actually, if you just wet the back of the finer grits with water they will often stick well enough without adhesive. Perhaps you will enjoy reading this: https://www.toolsforworkingwood.com/store/more/lappingfilm.html

Doug

Pat Barry
01-15-2016, 1:11 PM
Its good to know that 13 year old threads such as these still spurr comments :)

Doug Hepler
01-15-2016, 1:51 PM
Pat,

I accidentally resurrected this thread when I responded without noticing the date of the OP. I thought, "Whoops" when I finally noticed, but now I think it was a happy accident.

Doug

Mike Ontko
01-15-2016, 3:17 PM
Its good to know that 13 year old threads such as these still spurr comments :)

I was a little click-happy this morning and didn't even notice the original posting date. ><

Myk Rian
01-15-2016, 3:21 PM
Does everyone know this thread is 13 years old?

Brian Henderson
01-15-2016, 3:55 PM
Does everyone know this thread is 13 years old?

Does it matter? So long as the question is still relevant, which clearly it is because people are still talking about it, what difference does it make?

Myk Rian
01-15-2016, 5:28 PM
No, it doesn't matter. Just don't expect the OP to join in. Hasn't been around for 6 years.

glenn bradley
01-17-2016, 10:19 AM
Can anybody suggest me which sand paper I should get?


My sandpaper sources are LeeValley/Veritas and Tools for Working Wood.

I also get things from Tools for Working Wood but, any source for 3M micro abrasive film would do. I have even gotten it from Amazon. 15, 5 and .3 micron are y finishing grits and no spray adhesive will lay down smooth enough to not botch that up. I do see people simply use water to keep things put but, I have had a few "opps" moments with those and prefer the adhesive films. Conversely I do use spray adhesives up to about 600 grit. I also use polished tile for those coarser grits switching to glass for the finer grits.


Its good to know that 13 year old threads such as these still spurr comments :)

Too true. Good info and conversation have demonstrable value. Even threads about tool models no longer made can be of value to the "next" owner of said tool. Archival discussion is a great part of the value of a forum. I also find it useful to review old discussion of the latest "X" that is all the rage and see how it stood up over time ;-)

Tom M King
01-17-2016, 11:15 AM
Water, by itself, holds just fine on the 9x12 Granite surface plates that Woodcraft sells, and puts on sale a couple of times a year. The only thing I sharpen with paper any more are jointer knives.

jim mills
01-17-2016, 11:50 AM
Whats "scary sharp"?

David Eisenhauer
01-17-2016, 12:29 PM
Google "Scary Sharp" and you should be able to pull up the original description of a method developed (or described by the original author) for sharpening plane irons, chisels, etc by using sandpaper fixed to a dead-solid flat surface such as a piece of glass, granite cut-off or a home center tile. The sharpening goes through a progression of sandpaper grits, coarse-to-finer. At the very least, the "scary sharp" method is a good and fairly inexpensive introduction to sharpening woodworking tool edges to an edge that is effective for cutting wood. Many sharpeners move on to other methods, many stay with it, and, others, use the scary method for "grinding" the main bevel on very, very dull or damaged blades, then move on to some type of stone for the fine sharpening.